Inoculation with Bacillus alters nitrogen uptake and metabolism in roots of Diospyros lotus under wheat straw addition in soil

Abstract

A 15N-labelling technique was carried out to investigate the effect of wheat straw co-application with Bacillus nealsonii, Cohnella, and Paenibacillus lautus on N uptake and assimilation in Diospyros lotus. Wheat straw combined with Bacillus increased the plant height, biomass accumulation, photosynthetic capacity, and uptake of 15N by roots, with 15N accumulating mainly in leaves of D. lotus. The NO3--N content in roots and leaves were decreased by wheat straw co-application with Bacillus, whereas NH4+-N, soluble protein, and total N contents were increased. Wheat straw addition promoted the activities of nitrate reductase, glutamine synthase and glutamate synthase in roots rather than in leaves. These N assimilation enzymatic activities, and glutamic-oxaloacetic transaminase and glutamic pyruvic transaminase activities were markedly increased by wheat straw combined with Bacillus. Moreover, the combined application of wheat straw and Bacillus, particularly B. nealsonii, improved the N use efficiency. These findings suggest that the combined application of wheat straw and Bacillus improved D. lotus growth by increasing N uptake, metabolism, and utilisation efficiency.

Keywords

• 15n-uptake
• nitrogen assimilation
• persimmon tree
• nutrition
• isotope